Grass-fed certifications compared: AGA, AGW, OPT and USDA Organic

By the grassfed.food editors. Updated October 26, 2026.

If you want meat or milk from animals that ate only grass and forage, look for the American Grassfed Association (AGA), Certified Grassfed by AGW, or OPT Certified Grass-Fed Organic seal. All three keep grain out of the regular diet (with narrow exceptions explained below) and have farms inspected. USDA Organic and Animal Welfare Approved are useful labels, but neither one promises a grass-only diet, and a plain “grass fed” claim with no seal has no on-farm audit behind it.

What the labels mean, in one table

A few terms first. Forage is the leafy part of plants that grazing animals eat: pasture grass, legumes like clover, and stored forms such as hay and silage (fermented chopped forage). Ruminants are cattle, bison, sheep and goats. Dry matter intake is how much an animal eats with the water weight removed, which is how feed rules are measured.

The sections below explain each label. For all the seals we track, see our certifications page.

American Grassfed Association (AGA)

AGA writes its own standards and has farms inspected against them. Its ruminant diet rule is simple: forage is the only feed from birth to harvest, apart from mother’s milk and free-choice vitamins and minerals. Hay, haylage and silage are allowed when bad weather or poor pasture makes grazing hard.

AGA’s drug rule is broad. Its standard bans every type of antibiotic, hormone and ionophore (a feed additive used to change how cattle digest feed). A sick animal that needs a banned medicine must be treated, then tagged and removed from the certified program.

Other AGA rules worth knowing:

• Animals must be born and raised in the United States.
• Animals live on pasture and may be confined only for emergencies or routine handling such as roundups, sorting, shipping and weaning.
• Animals cannot be cloned or genetically engineered.
• Farms are inspected by independent third parties at least every 15 months.

AGA also has standards for dairy cattle and for pastured pork. The pork standard is separate, and the diet rules above are the ruminant rules, so don’t assume an AGA seal on pork means the same thing as one on beef.

Certified Grassfed by AGW

A Greener World (AGW) is a certifier that runs several labels. Certified Grassfed by AGW is an add-on to its Animal Welfare Approved label: a farm must meet the AWA welfare standard first, and the grassfed rules sit on top.

The diet rule is close to AGA’s. After weaning, animals eat only grass and forage for life. The standard specifically bans grain, grain by-products, feed concentrates, corn and soy. Urea is banned in supplements, and molasses is allowed only as a carrier for vitamins and minerals.

There is one exception you should know about. In a drought or similar emergency, a farm can apply to feed sprouted grains for up to 25% of daily dry matter. AGW must accept the request before the farm uses it. Other rules include:

• Records that trace each animal from birth to slaughter.
• For cow dairies, at least one AWA audit cycle and a year of 100% grassfed feeding before certification.
• A ban on clearing old-growth forest for certified land.

Certified Grassfed covers beef cattle, dairy cattle, bison, and meat and dairy sheep and goats. It does not cover poultry or pigs. Its confinement and drug rules come from the AWA standard described next.

Animal Welfare Approved (AWA)

Animal Welfare Approved is a welfare label, not a grass-fed label. Every Certified Grassfed farm must also meet it, which is why it belongs in this comparison. AGW says AWA animals spend their whole lives outdoors on pasture or range, and that auditors visit every farm in the program at least once a year.

The beef standard shows what AWA does and does not promise:

• Cattle must have pasture access at all times.
• At least 70% of the diet, by dry matter, must be long-fiber forage from weaning on. The standard does not ban grain in the rest of the diet; it only recommends keeping grain and soy to a minimum.
• Feedlots are banned, and so is routine sale of cattle to feedlots.
• Routine antibiotics, given to healthy animals or to speed growth, are banned. Sick animals must be treated, then wait twice the normal drug withdrawal time before slaughter for AWA meat.
• Growth hormones are banned.
• Transport to slaughter is generally limited to eight hours.

AWA covers many species, including cattle, bison, pigs, sheep, goats, laying hens, meat chickens, turkeys, ducks and geese. If a package says only “Animal Welfare Approved,” expect high-welfare pasture-based farming, but not a grass-only diet.

OPT Certified Grass-Fed Organic

This program was launched in 2019 by two organic dairy brands, Organic Valley and Maple Hill, and is administered by Organic Plus Trust (OPT), which accredits certifiers such as OEFFA to offer it. A farm must be USDA Organic first, so every organic rule on feed, drugs and living conditions applies. The OPT rules then tighten the grazing requirements:

• A grazing season of at least 150 days, compared with at least 120 days for organic.
• At least 60% of dry matter intake from grazing, compared with at least 30% for organic.
• A forage diet of pasture, hay and haylage. Grain crops can be grazed or fed only at an early growth stage, before they reach boot, bloom or tassel (roughly, before the seed head appears). Grain may also serve as a carrier in mineral supplements.
• Some non-forage feeds, such as molasses, kelp and beets, within daily limits. OEFFA’s summary does not give the limits.

OPT also certifies the supply chain. Milk can be sold as OPT grass-fed only if the processing plant is certified too, and the same goes for the slaughter plant for meat. Inspection is yearly, and OEFFA handles the OPT paperwork alongside a farm’s organic inspection and renewal.

You will see this seal mostly on dairy products. We could not find a public list of OPT-certified farms.

USDA Organic

USDA Organic is a federal standard, and every certified farm is inspected each year by a USDA-accredited certifying agent. Certifiers must also make unannounced visits to at least 5% of the operations they certify each year. It is a strong label, but it is not a grass-fed label.

For cattle and other ruminants, organic rules require:

• All agricultural feed must be certified organic. The feed rule does not ban grain, and the finishing rule describes organic slaughter stock as typically grain finished.
• Grazing throughout a grazing season of at least 120 days a year, with pasture supplying at least 30% of dry matter intake on average over that season.
• Year-round outdoor access. Animals cannot be kept indoors full time.
• Grain finishing on a feedlot or yard is allowed for up to one-fifth of the animal’s life or 120 days, whichever is shorter. The 30% grazing minimum does not apply during finishing.
• An animal treated with antibiotics cannot be sold as organic, and hormones cannot be used for growth or production.

So organic beef can be grain-finished, and organic milk can come from cows fed organic grain. If you want both organic and grass-only, look for the OPT seal. To check whether a farm’s organic certification is current, search the USDA Organic Integrity Database by state, city, product or certifier.

A “grass fed” label with no seal

The US Department of Agriculture (USDA) once had a voluntary grass-fed marketing standard, run by its Agricultural Marketing Service. It was withdrawn effective January 12, 2016, after the agency decided the claim fell outside its authority.

Today, the meat label claim is reviewed by USDA’s Food Safety and Inspection Service (FSIS). Its 2016 guidance says “grass fed” on meat labels means the animals ate only forage after weaning, with no grain, and had continuous pasture access during the growing season. To get the claim approved, a company submits written documents, including a signed description of the animals’ diet. There is no FSIS inspector on the farm checking that diet.

FSIS has tightened its guidance twice since then:

• 2019: Feedlot beef cannot be labeled grass-fed. Percentage claims, such as cattle fed partly grass and partly corn, must describe the actual diet rather than say “85% grass-fed.”
• 2024: FSIS strongly recommends third-party certification for animal-raising claims. The guideline is nonbinding, so companies are not required to follow it.

Two practical points follow. First, an uncertified “grass fed” claim says nothing about antibiotics or hormones. AGA has pointed out that FSIS guidance does not address those. Second, the FSIS guidance is about meat labels. We did not find a federal grass-fed definition for milk or cheese in the sources we checked, so ask dairy farms directly.

Many small farms raise animals on grass without paying for certification. With those farms, you have to ask the questions yourself.

How to use this when you shop

1. Want grass only? Look for AGA, Certified Grassfed by AGW, or OPT. These are the three seals in this guide that keep grain out of the regular diet and audit farms. Each has narrow exceptions, described above.
2. Read the species. The grass-only rules in this guide are written for ruminants. AGA’s pork standard and AWA’s pig and poultry standards are separate, so don’t read them as grass-only.
3. Treat organic and AWA as different promises. Both are audited every year, but neither requires a grass-only diet.
4. Check the certification. Use AGA’s producer search, AGW’s online directory, or the USDA Organic Integrity Database. A seal on a farm website is only as current as the farm’s last audit.
5. For uncertified farms, ask directly. Ask whether the animals ever get grain, including during finishing or winter, whether they are on pasture during the growing season, and whether they get antibiotics or hormones.

You can browse farms by state and see which certifications we have verified in our farm directory.

Sources

1. American Grassfed Association: Our standards
2. American Grassfed Association: Find a certified AGA producer
3. A Greener World: Certified Grassfed by AGW standards (2024)
4. A Greener World: Animal Welfare Approved
5. A Greener World: Animal Welfare Approved beef cattle and calves standards
6. A Greener World: Meet certified producers
7. OEFFA Certification: Organic grass-fed (OPT program)
8. FoodNavigator-USA: Organic Valley and Maple Hill launch new third-party certification (2019)
9. eCFR: 7 CFR 205.237, Livestock feed
10. eCFR: 7 CFR 205.238, Livestock health care practice standard
11. eCFR: 7 CFR 205.239, Livestock living conditions
12. eCFR: 7 CFR 205.403, On-site inspections
13. CCOF: Organic Integrity Database advanced search instructions (2025)
14. National Agricultural Law Center: USDA's AMS pulls standard for grass fed and naturally raised meat
15. American Grassfed Association: AGA responds to FSIS grassfed guidance (2016)
16. National Sustainable Agriculture Coalition: FSIS grassfed label claim update (2019)
17. FSIS Notice 28-24: Updated guideline on animal-raising and environment-related labeling claims
18. Hogan Lovells: USDA publishes updated guideline on substantiating animal-raising claims (2024)

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